/*
 * Copyright 2015-2025 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package fucksocks.common;

import java.io.Serializable;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import com.google.common.base.Preconditions;
import com.google.common.hash.Hashing;

import fucksocks.utils.UnsignedByte;


/**
 * 
 * The class <code>IP</code> represents an IP v4 address.
 * 
 * @author Youchao Feng
 * @date May 2, 2015 12:50:28 AM
 * @version 1.0
 *
 */
public class IP implements Comparable<IP>, Serializable {

  private static final long serialVersionUID = 1L;

  /**
   * Value of IP as long.
   */
  private final long value;

  /**
   * First number of the IP address.
   */
  private final int a;

  /**
   * Second number of the IP address.
   */
  private final int b;

  /**
   * Third number of the IP address.
   */
  private final int c;

  /**
   * Last number of the IP address.
   */
  private final int d;


  /**
   * Constructs IP by four numbers.
   * 
   * @param a First number of the IP address.
   * @param b Second number of the IP address.
   * @param c Third number of the IP address.
   * @param d Last number of the IP address.
   */
  public IP(int a, int b, int c, int d) {

    Preconditions.checkArgument(checkRange(a) && checkRange(b) && checkRange(c) && checkRange(d),
        "Each number of IP must in 0 ~ 255");
    this.a = a;
    this.b = b;
    this.c = c;
    this.d = d;
    value = this.toLong();
  }

  /**
   * Constructs IP by a long integer.
   * 
   * @param ip IP as Long integer.
   */
  public IP(long ip) {
    Preconditions.checkArgument(ip <= 0xffffffffL && ip >= 0, "Unvalid IP");
    value = ip;
    a = (int) (ip >>> 24);
    b = (int) ((ip & 0x00ffffff) >>> 16);
    c = (int) ((ip & 0x0000ffff) >>> 8);
    d = (int) (ip & 0x000000ff);
  }

  /**
   * Constructs IP by bytes.
   * 
   * @param address Bytes of address.
   */
  public IP(byte[] address) {
    a = UnsignedByte.toInt(address[0]);
    b = UnsignedByte.toInt(address[1]);
    c = UnsignedByte.toInt(address[2]);
    d = UnsignedByte.toInt(address[3]);
    value = this.toLong();
  }

  /**
   * Creates a IP instance by a string.
   * 
   * @param ip IP as a string. such as "192.168.1.1".
   * @return Instance of <code>Ip</code>.
   */
  public static IP parseFromString(String ip) {
    String regex = "\\s*(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\.(\\d{1,3})\\s*";

    Pattern pattern = Pattern.compile(regex);
    Matcher m = pattern.matcher(ip);

    Preconditions.checkArgument(m.find(), "IP string should match the regex:%s", regex);

    int a = Integer.parseInt(m.group(1));
    int b = Integer.parseInt(m.group(2));
    int c = Integer.parseInt(m.group(3));
    int d = Integer.parseInt(m.group(4));

    return new IP(a, b, c, d);
  }

  /**
   * Gets max IP which represents <b>255.255.255.255]</b>.
   * 
   * @return Max IP address.
   */
  public static IP MAX_IP() {
    return new IP(0xffffffffL);
  }

  /**
   * Gets minimum IP which represents <b>0.0.0.0</b>.
   * 
   * @return　Minimum IP address.
   */
  public static IP MIN_IP() {
    return new IP(0L);
  }

  public int getA() {
    return a;
  }

  public int getB() {
    return b;
  }

  public int getC() {
    return c;
  }

  public int getD() {
    return d;
  }

  /**
   * Gets next IP address. If the IP address dosen't have next IP then return <code>null</code>.
   * 
   * @return　Next IP address.
   */
  public IP nextIP() {
    return new IP(value + 1);
  }

  /**
   * Gets previous IP address. If the IP address dosen't have previous IP then return
   * <code>null</code>.
   * 
   * @return Previous IP adderss.
   */
  public IP preIP() {
    return new IP(value - 1);
  }

  /**
   * Returns <code>true</code> if the IP is local IP address.
   * 
   * @return <code>true</code> if the IP is local IP address.
   */
  public boolean isLocalIP() {

    return IPRange.AClassLocalIPRange().contains(this)
        || IPRange.BClassLocalIPRange().contains(this)
        || IPRange.CClassLocalIPRange().contains(this);
  }

  /**
   * Returns <code>true</code> if the IP can be used in Internet.
   * 
   * @return <code>true</code> if the IP can be used in Internet.
   */
  public boolean isUseInInteret() {
    return !isLocalIP();
  }

  /**
   * Returns IP as a long integer.
   * 
   * @return IP as a long integer.
   */
  public long toLong() {
    long a = this.a;
    long b = this.b;
    long c = this.c;
    long d = this.d;
    return ((a << 24) | (b << 16) | (c << 8) | d);
  }

  public static boolean isValid(String ip) {
    try {
      IP.parseFromString(ip);
    } catch (Exception e) {
      return false;
    }
    return true;
  }

  @Override
  public int compareTo(IP ip) {
    return (value > ip.getValue() ? 1 : value < ip.getValue() ? -1 : 0);
  }


  public long getValue() {
    return value;
  }

  @Override
  public String toString() {
    return String.format("%s.%s.%s.%s", a, b, c, d);
  }


  @Override
  public boolean equals(Object obj) {
    if (obj instanceof IP) {
      IP ip = (IP) obj;
      if (getValue() == ip.getValue()) {
        return true;
      }
    }
    return false;
  }


  @Override
  public int hashCode() {
    return Hashing.md5().newHasher().putInt(a).putChar('.').putInt(b).putChar('.').putInt(c)
        .putChar('.').putInt(d).hash().hashCode();
  }


  /**
   * Returns <code>true</code> if the number is in 0~255.
   * 
   * @param num a number.
   * @return <code>true</code> if the number is in 0~255.
   */
  private boolean checkRange(int num) {
    return num >= 0 && num <= 255;
  }


}
